Last week I had a local concrete company form and pour a monolithioc slab for a garage. The ground was soft top soil and I was concerned about it being soft. It did later compact an was very hard, but then it rained and was a big soupy mess. They came on out and covered it with plastic and poured the concrete even though muddy. They stomped around in it and it was no longer level nor compact, should I be worried.

Last week I had a local concrete company form and pour a monolithioc slab for a garage. The ground was soft top soil and i was concerned about it being soft. It did later compact an was very hard, but then it rained and was a big soupy mess. They came on out and covered it with plastic and poured the concrete even though muddy. They stomped around in it and it was no longer level nor compact, should I be worried.
I would be very worried, depending on climate the slab will crack, depending on rain fall it could sink a little

I've torn up a lot of concrete slabs and one thing I have learned is that you can do everything right and you will still get cracks, or you can do nearly nothing right and the slab is solid for years. I've seen slabs poured right on topsoil before and they do fine. Obviously, the best is to have a compacted stone base at least 4 inces thick, but since that isn't the case I would try to address one of the concerns a stone base alleviates; namely water and the damage it can do upon freezing. You could ensure that the ground slopes away from the slab so that water from rain won't get under the slab. If necessary, you could even run a drain tile around the slab. I'm in Wisconsin so freezing is always a concern, but if it isn't for you, then I think you might be all right. Did they put rebar, wire, or use fiber mesh in the concrete?